A parking assistance device is conventionally known which assists parking a vehicle when the vehicle is to be parked, based on image information displayed on a display device (for example, a car navigation system) provided in the vehicle. Image information is obtained by, for example, processing a camera image captured by an in-vehicle camera provided at, for instance, the rear of a vehicle. Examples of such image processing include image conversion processing for converting a camera image into an overhead image, and image recognition processing for recognizing a marker indicating a parking area in the overhead image (see Patent Literature 1, for example).